First, you will need to unscrew the bottom cover from the main section of your wireless microphone. The following images will demonstrate the point at which this applies:User-added imageUser-added imageCareful removal of this cover will expose the battery compartment, protected by a clasp mechanism (see below) that can be opened by gently pulling the tab towards the bottom end of the device.User-added imageThis final image shows where your two AA batteries can be replaced. Once replaced, simply return the clasp mechanism to the original position, affix the battery compartment cover back on the microphone and continue to enjoy use of your ULM202USB.User-added image